Step-by-step explanation
From the statement, we know that the store:
0. buys instruments and then sells them for 30% more than they paid,
,
1. during a 20% sale, the store offers a clarinet for $93.60.
(1) From point 1, we know that the relation between the original price (Po) and the selling price (Ps) is given by:
![P_s=(1+0.3)*P_o=1.3*P_o\Rightarrow P_o=(P_s)/(1.3).](https://img.qammunity.org/2023/formulas/mathematics/college/gw4y9q3dbww7984st17k4bdqy93ct2n8k5.png)
(2) From point 2, we know that the relation between the final price with the discount (P_f) and the selling price without the discount (Ps) is:
![P_f=(1-0.2)*P_s=0.8*P_s\Rightarrow P_s=(P_f)/(0.8)=\frac{\text{ \$93.60}}{0.8}=\text{ \$117.}](https://img.qammunity.org/2023/formulas/mathematics/college/h0iyr3uv4ak93atvmoz2bnti45rccm077m.png)
(3) Finally, replacing the value of Ps in the equation of point (1), we find that the original price of the instrument was:
![P_o=\frac{\text{ \$117}}{1.3}=\text{ \$90.}](https://img.qammunity.org/2023/formulas/mathematics/college/5v3u9wh99d8g9u8egfia2jdi7akwk7psb7.png)
Answer
The store paid approximately $90 for the clarinet.